1. Field of the Invention
The present invention relates to a data acquisition control method and system. The invention is particularly adaptable to optical recognition systems which employ techniques for processing a wide range of inputted images or patterns for recognition. The system of the invention may be portable, i.e. having at least a hand movable wand or the like adapted to be moved or scanned along one or more lines of print, type, etc. It will of course be apparent that many features of the invention are also adapted to recognition devices other than movable, hand held or optical and it is hence not intended to be so limited in many of its aspects.
2. Description of the Prior Art
The need for and popularity of optical image or pattern recognition systems has recently grown enormously due to the tremendous popularity of word processing systems which may employ an optical character reader to input data into the system. In these applications it has been traditional to employ large mechanical structures for controlling the device that actually scans the characters and converts the optical data into an electrical signal. These scanning structures automatically control the alignment of the sheet being read with the scanning head and also the speed at which the device scans.
The size and complexity of such automatic mechanical scanning structures render them inappropriate for numerous applications in which portability or selectivity is desirable. To enhance portability, those working in this field have attempted to eliminate the necessity for the large mechanical scanning structure. Thus, U.S. Pat. No. 3,991,299, Chadima, Jr., et al. discloses a bar code scanner in which a pen-shaped instrument is drawn across the bar code in order to read it.
Others have attempted to develop hand-held readers for codes other than bar codes. U.S. Pat. No. 4,377,741, Brekka et al. discloses a hand-held optical code reader. However, when advancing from relatively simple bar code readers to more general character scanners, problems arise for example with respect to alignment of the scanning head with respect to the characters an the speed with which the scanning head proceeds over the characters. Lacking the mechanical structure for controlling these variables, a portable unit must employ alternative solutions to minimize problems associated with misalignment, skewing, variations in scanning speed, and indistinct spacing.
U.S. Pat. Nos. 3,918,029 and 3,735,350, both to Lemelson, teach a scanning system which provides a solution to the alignment or skew problem. A guide is provided for directing a scanning element across a row of characters. Thus, prior to scanning, the characters are aligned with the guide. Then, it becomes fairly simple to maintain alignment of the scanning head with the row of characters by sliding the head along the guide. However, even in these patents, a mechanical guide is required, and codes and not characters are being scanned. A further problem occurs that although skewing errors have been removed, it is still necessary to recognize the scanned characters. If the speed of scanning varies or even is different from a preestablished ideal speed. The proportions of characters that have been read and converted into electrical signals will vary, thus rendering the problem of recognition extremely difficult.
U.S. Pat. No. 3,947,817, Requa, which discloses a portable, hand-held optical code reader, mentions the problem that variations in scanning speed, producing expansions and contractions of data, render recognition difficult. However, the solution suggested by Requa involves complex data processing. Other code reading and character recognition devices are disclosed, for example, in U.S. Pat. No. 3,747,066, Vernot and U.S. Pat. No. 3,873,972, Levine.